This invention relates to encapsulation and particularly to the production of small or minute capsules constituted by a skin or a thin wall of organic composition enclosing a body of material such as a liquid. The process of this invention is directed to the production of such capsules which may be produced to a predetermined size, and in a convenient and rapid method by chemical reaction in situ, wherein a suspension or a collection of discrete spheres or capsular spheroids is formed in a body of liquid which then may be readily separated or retained and used in said liquid.
Capsules of this nature and description have a variety of uses, such as for containing dyes, inks, chemical reagents, pharmaceuticals, flavoring materials, fungicides, bactericides, pesticides, such as herbicides, insecticides and the like, which substances can be dissolved, suspended or otherwise dispersed in or as the material to be enclosed by the capsule. The material to be encapsulated can be employed in the initial dispersion at a temperature above its melting point, or dissolved or dispersed in suitable water-immiscible organic solvent. The nature of the water-immiscible material to be encapsulated can be organic or inorganic in origin. Once encapsulated, the liquid or other form is preserved until it is released by some means or instrumentality that breaks, crushes, melts, dissolves or otherwise removes the capsule skin, or until release by diffusion is effected under suitable conditions. An important specific aspect of this invention, together with other features and advantages contemplated by the invention, is the procedure for polymerization involving the reaction between polyisocyanate monomers, to produce a capsular skin of polyurea.